Process and apparatus for extracting juice from sugar cane



M. B. SPAULDING Filed Aug. 17. 1928 CRUSHER 7 #PRIMAEY :rum,

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May 30, 1933.

PROCESS AND APPARATUS FOR EXTRACTING JUICE FROM SUGAR CANE SECONDARY J'UlC/EI Patented May 3%, 1933 UNITED STATES PATENT OFFICE MORRIL B. SPAULDING, OF WAYNE, PENNSYLVANIA Application filed August 17, 1928, Serial The present invention relates to improvements in a process of and apparatus for extracting and treating juices from sugar cane, one object of the invention being the provision of an apparatus which will dispense with the present type of trash screen and elevator and its auxiliaries for handling the raw juice and the installation of the necessary screen unit for only primary juices separate and apart from the sugar mill tandem; and with the elimination in major part of the deterioration of the mill juice pans, collecting and delivery canals, and the usual ordinary steel or cast-iron installation V of the sugar mill tandem, the process further providing for the elimination, under certain conditions, of the filtering presses for the defecated juice, either in whole or in part.

A further object of this invention is the provision. of an apparatus by which the primary sugar juices, viz those over 10 Brix, as produced by and from a crushing mechanism and the primary first rolls, together with its contained bagasse, etc., will be automatically and mechanically screened, and the filtrate will be delivered to the sugar house for processing, while the over-size, viz all of the solids too large to pass through the openings of the screen medium, with its contained pieces of cane stalk, bagasse and bagasillo, will be delivered to and combined with a secondary juice, viz the juice below 10 Brix or resulting from dilution with wash water to be mechanically pumped or delivr ered onto a mill mattress at a selected point.

A still further object of this invention is the provision of an apparatus by which the cane as crushed and macerated to produce the secondary sugar juices, and which are assumed to be below 10 BriX, will be mechanically handled or pumped and delivered with or without screening upon the crushed cane and mattresses of the sugar mill tandem at the point selected, thus providing a means whereby the secondary sugar juices are thoroughly commingled with the macerated cane so that the juice to be extracted therefrom will produce a primary juice or a juice that is separated into a primary and an oversize for the continuous operation.

No. 300,276, and in Cuba June 16, 1928.

A still further object of this invention is the provision of an apparatus and process by means of which the last and final treatment of the sludge or the cachaza produces a residue that will contain such a small amount of sucrose as to be practically useless, thus rendering the use of the filter process, as at present operated, unnecessary.

A still further object of this invention is the provision of means whereby the corrosion and galvanic deterioration effect upon the juice pans, canals or sugar sluices, and other ferrous parts, piping or tubing, or metals subject to usual deterioration of the sugar mill, will be practically eliminated in that the same will be covered with or constructed of a corrosive and galvanic action resisting material or alloy, the same being polished so as to have the least possible skin resistance to the sugar juices and the products of the sugar mill, and also all parts, canals or sluices being so shaped as to be of the greatest capacity and to require a minimum amount of material for their manufacture.

Many different installations can be made to carry out the present invention, and it is, therefore, not desired to limit the invention to any particular arrangement, but in the accompanying drawing several forms have 0 been shown, in which drawing -Figure 1 is a diagrammatic view of one form of the complete extracting mill using compound maceration;

Figure 2 is a similar view of a modified form using simple maceration;

Figure 3 is a cross-section through one of the sluices or canals for carrying the sugar juices; and

I Figure 4: is a perspective view of a portion of the preferred type of screen used with the present apparatus.

Referring to the drawing, and more particularly to Figure 1 thereof, the numeral designates a crusher, or any number that may be desired, while the respective mills are indicated as numbers 1, 2, 3 and a, four being shown, although there may be more to form the tandem.

Mills number 1 and 2, with the crusher 5,

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are designed to deliver primary juices to the straining mechanism or screen 8, through the respective carriers 6 and 7. The pipe 9 delivers the filtrate to the pump 10 which forces it through the pipe 11 to the sugar process house (not shown).

The carrier 12 conducts the over-size, viz the material which cannot pass throughthe screen medium or strainer, from the straining mechanism to the carrier 13 which, in turn, receives the secondary sugar juice, viz that below 10 Bria from mill number 3 and delivers it with the over-size received through the carrier 12 from the screen 8 to the pump 1 1 which forces them through pipe 15 for delivery through nozzle 16 or intake side of the cane ma tress at its entry or intake side of the mill or macerator 1. Thus the unscreened secondary juices of the cane stalks, bagasse and bagasillo are deposited upon the mattress before the mattress is pressed, miXed and filtered therethrough, and is also pressed with the cane in passing through the rolls thereof.

The carrier 17 delivers the secondary juices from mill number *1 to the pump 18, which, in turn, delivers the same through the pipe 19 and the nozzle 20 onto the mattress at the intake side of mill number 2. The installation as shown for mill number 4 illustrates the requirements and methods of process for: each additional mill unit whenoperating with the compound maceration, and this may be continued to other stages, as may be found necessary.

By this particular arrangement, the uices and residues, comprising the over-size from the screen 8 and the juices known as secondary juices from the mills numbers 3 and el are delivered by means of the pumps 1 1 and 18 to and at the intake side of the macerators of the respective mills numbers 1 and 2, and, where so desired, this operation can be continued indefinitely to produce the desired maceration liquid for the sugar mill tandem.

In the arrangement shown in Figure 2, where a simple maceration is employed, and which carries out the present process, the crusher E is located to feed the cane mattress to the mill A, while juice produced by the succeeding macerators or mills B, C and D are combined, one with another, so that the over-size from the screen 21 below the mill A will be delivered through the carrier 25 to the pump 27 and thence through the pipe 28 to the outlets 29 and 30 to the mattress at the intake sides of the mills A and B.

The primary juice from the crusher E and the mill A is delivered to the mechanical strainer 21, the filtrate therefrom being delivered through car ier 22 to the pump 23 which forces it through the pipe 2 1 to the sugar house process. The over-size from the strainer 21 enters the carrier 25 and is delivered thereby through the carrier 26 to the pump 27 which forces it by way of the pipe 28 to the nozzles or outlets 29 and 30, where the same is delivered upon the cane mattress before it enters the macerators or mills A and B.

The unscreened secondary juices, viz those below 10 BriX, delivered from the mills B, C and D will also be delivered by the carrier 26 to the pump 27 and thence with the over-size from the strainer 21 through the pipe 28 onto the cane mattress of the mills A and B. Thus the unscreened secondary juices from the mills B, C and D are combined with the over-size from the screen 21 to be acted upon in a similar manner to the construction set forth in Figure 1.

In this arrangement of apparatus each following mill or macerator has its product or secondary juice delivered to the cane mattress of a mill unit'in advance thereof or preceding that from which it originates, thus carrying out substantially the same effeet as already illustrated in Figure 1, the difference being that all unscreened second ary juices are combined before they are de livered from the three mills B, C and D upon the mill mattress as it enters the respective mills A and B.

here so desired, the filtrate from the cachaza or sludge can be delivered at various stages of the process, as for instance, in Figure 1, it is delivered at two points, namely; through the carriers 13 and 17 into the carriers 13 and 17, respectively, or, as shown in Figure 2, it is delivered by means of the carrier 26 into the carrier 26.

The canals or sluices in the present apparatus are preferably constructed as shown in Figure 3, the same being ellipsoidal in crosssection and composed of an outer carrying body 31 having a non-corrosive inner surface 82, this surface 32 being preferably composed of corrosive and galvanic resisting alloys preferably of chromium, cadmium, nickel or cobalt, without preference, the same being polished so as to provide as little skin resistance or friction to the juices and material carried thereby as possible, and yet in no way contaminate the juices as they are delivered from one place to another, and in which no galvanic action, such as that which occurs between copper and iron in the present mills, takes place.

The screens 8 and 21 are preferably of the type shown and described in my U. S. Patout No. 1,709,826, dated April 16, 1929.

The screens 8 and 21 may be of the form shown at 33 in Figure 4 where the screen is shown as formed with the imperforate cross-shaped port-ion 34 and finely perforated portion 35, the imperforate portions,

providing an imperforate reinforcement for the screen that is integral with the perf'o-,

rated portion, the perforations being of the desired size to screen the juice and also the cachaza so that the best results are obtained and the cleanest products result.

The filtrate as obtained from the filter presses is usually sent back into the sugar house circuit for further defecation, and continues being processed, but I have proposed to use this filtrate as obtained either from the filter presses, or from the herein described screen when handling the cachaza.

1. As a maceration liquid to be added with any one of the secondary juices as returned to the mill mattress.

2. As dilution liquid to be added to the oversize from the filtering of the primary juices, this to enable the pump to properly handle the coarse material as thus obtained, and without combining same with a secondary juice; and which may be convenient under some operation conditions.

By the employment of a screen to take care of only the filtrate and oversize, the secondary juices not being screened, the trash elevator and its auxiliaries are eliminated, and it is evident. that by automatically and mechanically screening the primary sugar juices by the screen shown in Figure l and as particularly shown and described in my U. S. patent above referred to, the amount 01 defecation mud or cachaza is greatly reduced and the final resultant cachaza is so reduced in volume and in contained sucrose as to render it useless or undesirable for further treatment and the extration by filter press process.

It is also evident that by the present apparatus all sugar juices coming from the sugar mill tandem will be divided into two classes, namely; the primary juice from the crushers and the first rolls, which is usually higher than 10 Brix, and the secondary juice, which is assumed as below 10 Brix.

By this process and apparatus, the secondary juices which are assumed as being below 10 Brix are not screened, but are mechanically pumped or delivered onto the mill mattress at the selected points, a pump of a centrifugal non-choking type being preferably used.

lVhere compound maceration is employed, the material produced by each roll unit is delivered to its individual special pump unit while with the simple maceration or single return, only one mechanical unit or trash pump is required for the return of the combined secondary juices.

I claim 1. In a process for obtaining sugar cane juices by successively crushing and macerating the sugar cane, separating the extracted juices in the first macerating process into a filtrate and an over-size, mixing the oversize with unscreened secondary juices of a succeeding macerator, and returning the mixture to the cane mattress of a preceding macerator.

2. In a process for obtaining sugar cane juices by crushing and macerating sugar cane, separating the juices from a plurality of primary macerators into a filtrate and an over-size, mixing the over-size with unscreened secondary juices of one of the succeeding macerators and delivering the mix ture upon the cane mattresses of the firstnamed macerators.

3. In a system of the class described, the combination with a train of mills, of means for separating the extracted juices from the first mill into a filtrate and an over-size, means for mixing the oversize with the unscreened secondary juices from the succeeding mills, and means for returning the mix ture directly to the intake side of the preceding mill.

4. In a system of the class described, the combination with a train of mills, of an oversize and filtrate screening device for the juice expressed by the primary mill, secondary juice conveying means including a pump leading from each of the succeeding mills and delivering the unscreened secondary juices from the succeeding mills directly to the cane mattress at the intake side of the respective preceding mills, means for delivering the oversize from said oversize and filtrate screening device to one of the secondary juice conveying and delivering means and mixing it with the juice in the latter, and means for deliverng such mixture directly to the cane mattress of the mill producing the oversize.

In testimony whereof I have hereunto set my hand.

MORRIL B. SPAULDING. 

